Steel Framed Multi Storey Car Parks by CORUS -- Gkk 14may2012

Corus Construction & Industrial

Steel-framed car parks

Contents

Avebury Boulevard multi-storey car park Milton Keynes

Contents

Contents 5

Introduction

Acknowledgements

Attributes of good car park design

This is the third edition of the Steel-framed car parks

Advantages of steel construction

brochure, and Corus would like to acknowledge the input of all previous contributors, specifically:

6

Outline design Dynamic efficiency

Compilers of the first edition published in 1995.

Flow patterns

• Bernard WJ Boys, formerly British Steel plc and the

Circulation design

• David Dibb-Fuller, Partner, Gifford and Partners

Steel Construction Institute 7

Ramp width and slope Car park layout

Compiler of the second edition published in 1998. • Colin S Harper, formerly British Steel plc now Corus.

9

Structural form Foundations

Corus would also like to recognise the contribution of

Column positions

the following organisations to the production of the third

Floor and frame solutions

edition of this publication:

Underground car parks Vehicle safety barriers

• The Steel Construction Institute

Deflection

• Bourne Parking Ltd.

Dynamic performance

• Caunton Engineering Ltd.

Stability

• Clugston Construction Ltd. • Hill Cannon (UK) LLP

16 Fire resistance

• Severfield-Reeve Structures Ltd.

18 Durability The steel frame Concrete floors Metal decking Waterproofing Refurbishment 21 Aesthetic design 22 Commercial viability 23 Latest developments Demountable car parks Wholly automatic multi-storey car parks 24 Sizing data sheets 28 Case studies 34 Bibliography 35 Support for the construction industry from Corus Construction & Industrial

Steel-framed car parks

3

Avebury Boulevard multi-storey car park Milton Keynes

Introduction

Introduction The multi-storey car park is a unique style of building; one in which all elements of the structure are normally exposed to the public.

This publication gives examples of good practical

Steel is also an ideal material for satisfying the

design that enable the structure to blend with all

requirements of ‘Rethinking Construction’:

environments whilst utilising the inherent versatility, elegance and economy of a steel frame.

• Reduced costs • Reduced time on-site

Fundamental design information is given to illustrate how

• Off site fabrication of primary structure

steel, with its ability to accommodate long clear spans

• Increased productivity

and minimise column sizes, can create aesthetically

• Certainty of budget and time

pleasing, economic, secure, user-friendly car parks.

• Improved efficiency in the use of materials • Reduced wastage

This guide is intended to assist the designer with the

• Safer construction

preparation of budget schemes, without the need for

• Improved quality

complex calculations at the outset. It does not however, relieve the designer of his responsibility for providing full

Steel solutions also have excellent sustainability

design data for the built structure. Further guidance is

credentials:

available in the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION).

• Composite construction uses materials more efficiently • Minimised waste

Attributes of good car park design

• Recycled and recyclable material

• Easy entry and egress to car park and stalls

• Adaptable construction

• Uncomplicated and logical traffic flow

• Lightweight construction leads to more efficient

• Unimpeded movement • Light and airy

foundations than for other forms of construction • Long life product

• Low maintenance • Safe and secure Advantages of steel construction This guide will demonstrate that steel construction is ideally placed to satisfy all the requirements of good car park design. Steel is: • Ideal for long spans • Lightweight • Robust • Fire resistant • Easily maintained • Vandal resistant • Minimalist • Economic

Steel-framed car parks

5

Outline design

Outline design The dimensions of large, standard and small size cars Stall width

the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION). These

Bin width Aisle

are well established and are presented in Table 4.1 of

dimensions form the basis of the geometry required for stalls, aisles and ramps. The minimum dimensions are based on the standard car and the bin size on the parking angle and stall width. This is shown in Table 1. Table 1. Effect of varying parking angle on parking bin requirements

Figure 1. One way flow, angled parking

Parking angle

• Two-way flow systems are more familiar to the user and if

Stall width (m) parallel to aisle

Aisle width (m)

2.3 2.4 2.5

3.25 3.39 3.54

3.60

60°

2.3 2.4 2.5

2.66 2.77 2.89

75°

2.3 2.4 2.5

45°

Bin width (m) (stall length 4.80m)

properly designed can achieve a higher flow rate than one-way systems. They require marginally more space

13.65 13.80 13.95

and are therefore less structurally efficient than one-way

14.85 14.95 15.05

parking as their use with angled parking can cause

4.20

2.38 2.49 2.59

4.98

15.45 15.50 15.55 15.60 16.55

90°

All

All

One way aisle 6.00

90°

All

All

Two way aisle 6.95

systems. Two-way systems are best used with 90° confusion to the driver.

Stall width Bin width Aisle

Stall width (m)

Dynamic efficiency The dynamic efficiency of a car park depends on the ease with which entry, egress and parking can be achieved. The general principle should be that cars cover as many stalls as possible on entry and as few as possible on exit. The layout of the exits and the size of the reservoir capacity are other major factors when considering dynamic efficiency. Flow patterns There are two flow patterns used in modern car park construction: one way and two-way flow. These can be combined with either 90° or angled parking. • One-way flow systems, if used with angled parking, provide a very good solution to the parking problem. They ensure easier entry and exit to stalls and allow significant flow capacities to be achieved with the self-enforcing flow pattern. Difficulties can arise when the intended flow is ignored and therefore good signage is required.

6

Steel-framed car parks

Figure 2. Two way flow, 90° parking

Circulation design

Circulation design Ramp width and slope

Split-level layouts (Figure 3) have good dynamic flow

The widths of the ramps should usually be no less than

rates and excellent structural efficiency. They can be

3.5m for a single ramp and 7.0m for a double ramp. It is

used with one-way and two-way circulation patterns

recommended that ramp widths are kept in line with

and a variety of ramp arrangements to achieve the

stall widths, for example with single flow traffic, the

desired performance.

ramp would be two stall widths wide and for two way traffic flow, three stall widths wide.

This is probably the most popular layout in the UK for car parks with row capacities greater than 24 cars. Entry

The slope of the ramp is dependent on the clear

and exit traffic are separated and the flow pattern is

headroom (2.1m minimum) and the structural zone. The

simple and uncomplicated. When built in steel, with

growth in popularity of the larger multi-purpose vehicles

column free spans, this layout will give the best

(MPV’s) has had an effect on the minimum clear height

combination of economy and operating efficiency.

and ramp length requirements. The shallower and wider the ramp, the better it will meet the needs of users. However less steep ramps are longer. Typical slopes range from 1:6 to 1:10. Steeper gradients may be used if transitions are provided at the top and bottom of the slope. Refer to the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION) for detailed guidance on rampwidths and slopes. The split-level system, shown in Figure 3, offers a method of reducing ramp length, whilst keeping the gradient within reasonable limits by staggering the parking levels by half a storey height. Figure 4. Flat deck layout

Flat deck layouts (Figure 4) are becoming increasingly popular for their simplicity of construction, clean lines and ease of use. They are particularly suitable in situations where the floor levels have to be matched to another building. This layout is less efficient than the split-level arrangement but can have comparable dynamic capacity for infrequent users. However the larger search paths can be frustrating for frequent users where a ‘parking ramp’ solution may be more acceptable. Figure 3. Split-level layout

The layout illustrated (Figure 4) would be used for Car park layout

smaller car parks where the dynamic capacity is not

There are many layouts used for multi-storey car parks,

critical. Two-way flow is used with external rapid entry

each offering specific advantages to the user and

and exit ramps.

operator. The layouts indicated are those most commonly used in the UK. All are eminently suited to a steel-framed solution, which will be competitive on price and provide excellent performance.

Steel-framed car parks

7

Circulation design

The parking ramp shown is a single ramp with two-way flow. It offers ease of use combined with efficient usage of space. External ramps may be added if rapid exit from the park is required. In this case a one-way system would be preferred. Whichever type of layout is chosen, a number of key principles should be followed: • Keep it simple. What looks like a clever solution could be difficult for the user • Minimise the workload on the driver and avoid confusion as to where to go and what to do. This is solved partly by signs but mainly by good design. • Cover as many stalls as possible on the entry route Figure 5. Parking ramps

• Pass as few stalls as possible on the way out • Separate inward traffic from outward traffic if possible,

Parking ramps (Figure 5) may be used with great success where frequent users are the prevalent customers, for example, a large office. Their main advantage is that the user must pass all stalls on entry to the car park, resulting in a rapid search path and less frustration. Users can be disadvantaged when exiting the car park unless an express exit is provided.

Green Park Reading

without causing additional complications • Circulate to the right if possible so that the driver is on the inside of the turn

Structural form

Structural form The structural design of a car park will usually determine

However there may be occasions, for example, where

its quality as a user-friendly structure. The structural

the car park is beneath another form of structure with a

form should provide:

different span arrangement, where internal columns must be used (Figure 7). This arrangement has an

• Ease of entry and egress to and from stalls so that

impact on the column cross centres and a comparison

users can gain rapid entry and exit without the risk of

of possible geometry for clear span and propped

damage to vehicle or injury to person.

alternatives is presented in Table 2.

• Few obstructions to movement. The driver should be guided through the park without encountering severe obstructions such as columns in the drive path and badly parked cars caused by inefficient design or layout. • A light and airy environment. The environment the car park provides will often determine how profitable it is. A light and airy environment should be one of the major goals of the car park designer. Steel is ideally placed to provide this type of environment because of its lightweight nature and long span capabilities. This can be further enhanced if open web sections are chosen. See case study 2. • A safe and secure environment. Today, personal security is high on the list of priorities for any building; car parks are no exception and due to their public nature they must be safe for users and their vehicles.

Figure 6. No internal columns to impede traffic flow

A building with minimal internal structure will help to enhance the feeling of security by making the area as open as possible with few barriers to sight lines. The light and airy environment made possible with steel will help to enhance the feeling of security required of these buildings. Foundations The design loading for car parks is given in BS 6399, which specifies an imposed loading of 2.5kN/m 2 for the parking areas and ramps. The loading on foundations is greatly influenced by the material chosen for the frame. Steel is the lightest practical construction material and will often allow the use of simple foundations where other, heavier materials will not. The type of foundation required is often the deciding factor on whether a project is viable. Steel is often the only viable

Figure 7. Alternative positions of columns impede traffic

construction material for multi-storey car parks. Column positions The desirable attributes indicated above will only be completely fulfilled if there are no internal columns (Figure 6). If steel is chosen as the frame material a clear span solution can be used for the majority of car parks.

Steel-framed car parks

9

Structural form

Table 2. Effect of internal columns on overall width No. of cars between columns

Column cross centres option (2.4m stall width)

Reduced column cross centres for clear span

2

(a) 2.400 x 2 } (b) +0.300 x 2 } = 5.7m (c) +0.150 x 2 }

4.8m

3

(a) 2.400 x 3 } (b) +0.300 x 2 } = 8.1m (c) +0.150 x 2 }

7.2m

4

(a) 2.400 x 4 } (b) +0.300 x 2 } = 10.5m (c) +0.150 x 2 }

9.6m

(a) Stall width (b) Clearance to column (c) Half column width

It is generally preferable to arrange longitudinal column and beam spacings to coincide with parking stall widths; the equivalent of one, two or three stall widths are the

Shear Connector Mesh Reinforcement

Transverse Reinforcement In-Situ Concrete A

most commonly used. Using a single width has the advantage of visually separating the stalls for the driver, but it is not suitable when using internal columns. With column spacing of two stall widths it is generally only necessary to use secondary beams when shallow profile

A PCC Slab

steel decking is used to form the slab. Other slab solutions may require secondary beams when the column

Steel Beam

spacing is in excess of two bay widths. Secondary beams are used to avoid propping of the floor during construction, to limit depth of construction and ensure economy of design. Floor & frame solutions A variety of floor systems can be used in multi-storey car park construction. The ultimate choice will depend upon

View on A-A Figure 8. Composite beam with PCC hollow core slab

many factors, such as height restrictions and structural layout. Five of the most common types of floor

Figure 8 shows hollow core pre-cast units used

construction used in steel-framed car parks are shown

compositely with the steel beams. To achieve composite

(Figures 8-12). With all the illustrated systems the steel

action, alternate cores of the precast units must be

beams may generally be designed either compositely or

broken out and filled with in-situ concrete for the

non-compositely. The exception is where precast units run

effective width of the slab. Additional transverse

parallel to the primary beam, in which case the primary

reinforcement is also required. A concrete topping

beam will be a non-composite design.

would normally be used to give adequate resistance to moisture penetration and to tie the pre-cast units together to form a monolithic floor slab. Detailed guidance is available in SCI publication P287, 'Design of Composite Beams Using Precast Slabs'. The system has the advantage that wider spacing of main beams can be achieved because of the pre-cast unit's spanning capabilities, and low self weight. Speed of construction will be improved over a solid slab, leading to greater cost savings on the scheme. In the non-composite version of this system the cores of the

10 Steel-framed car parks

Structural form

pre-cast units do not require to be broken out, this leads Reinforcing Mesh

to faster construction times at the expense of greater steel weight. The metal deck solution, shown in Figure 9, has been

Shear Connector Metal Deck

A

used for a small number of car parks in the UK. As well as performing a role as part of a composite slab, the metal deck also acts as permanent formwork to improve speed of erection and reduce cranage requirements compared with the other systems described. The

In-Situ Concrete

maximum unpropped span of these types of decks is around 4.5m (consult manufacturer's literature for exact

Steel Beam

details), therefore the spacing of the main beams cannot be greater than one stall width unless secondary beams are used. When metal deck is used in conjunction with composite A

beams, through deck welding of the shear studs is beneficial because it enables continuous sheets of decking to be laid on the steel beams prior to fixing the studs. It may also enhance the way in which the decking behaves as transverse reinforcement adjacent to the studs. However, in the potentially corrosive environment of a car park, the need, when using through deck welding, to keep the upper surface of the beams free of paint (to avoid contamination of the stud welds) may be unacceptable. This leaves the designer with four options: • Use shear connectors that are attached to the beams without the need for welding. A number of connectors that use shot-fired pins are available.

View on A-A

• Weld the studs to the beams in the fabrication shop, prior to applying the corrosion protection. With this

Figure 9. Composite beam and metal deck

solution the decking is best laid in single span lengths and butted up to the studs. This makes the decking less structurally efficient and requires stop ends to prevent the in-situ concrete escaping through voids. Alternatively, holes may be punched in the deck so that it can slot over the studs, but this may be more difficult to achieve in practice. • Use non-composite beams. • Use a combination of non-composite secondary beams and composite primary beams. The decking can then be laid in continuous lengths across the secondary beams, which are normal to the span of the primary beams.

Steel-framed car parks 11

Structural form

shear connectors welded to the top flange of the steel beam. These should be welded ‘in the shop’ so that corrosion protection can be applied. Transverse reinforcement will be required and additional bars may also be required at the stud location to act as bottom reinforcement.

Gap filled with expanding grout and covered with strip waterproof membrane Shear connectors Strip waterproof membrane

Deep decking enables the elimination of secondary

Galvanised reinforcing bars set into pre-cast slab

beams because it can span up to 9.0m. Deep decking

Steel beam

Figure 10. Slimdek® and deep decking

110mm thick pre-cast concrete deck with brushed finish

will provide the maximum benefit when used with Slimdek ®, as shown in Figure 10, typically spanning around 9.0m. Figure 12. 'Montex’, pre-cast slab system

A variation on the pre-cast slab design is the 'Montex' system illustrated in Figure 12 which is a proprietary Shear connector Reinforcing mesh

In-situ concrete topping Reinforcement

design using special slabs with hooped bars emerging from the ends of the units. These are used to tie the system together as illustrated in Figure 12. The void is filled with in-situ concrete and then covered with a strip waterproof membrane.

Transverse reinforcement

PC concrete slab

Underground car parks Steel beam

Steel sheet piles are ideal for producing an efficient, cost effective and quick retaining structure for underground car parks and deep basement car parks. Floors can be designed to act as struts for the finished structure, which can be utilised in the ‘Top Down’ construction method. This combined with the ability of a steel sheet pile

Figure 11. Composite beam with composite PCC slab and topping

Figure 11 shows a composite beam with composite pre-cast concrete slab and topping. The pre-cast slab in this case is solid and usually only 75mm to 100mm thick. This spans between beams, the maximum span being around 5m, allowing main beams to be spaced at two stall widths, without propping of the slab during construction. Composite construction is achieved with

12 Steel-framed car parks

retaining wall to accept vertical bearing loads make this form of construction particularly effective for car parks beneath new buildings. Further information on underground car parks is contained in the Steel Construction Institute publication SCI-P275: Steel Intensive Basements.

Structural form

Figure 13. @Bristol underground car park.

Figure 14. Pre-cambered cellular beams as used at the Buttercrane Centre car park, N. Ireland.

Vehicle safety barriers

other situations because users are either in motion

All car parks should be fitted with adequate vehicle

themselves, by walking, or sat in a car and isolated from

safety barriers to prevent accidental damage to the

external vibration by the suspension.

structure and restrain out of control vehicles. Edge barriers in particular should be adequate to restrain

Traditionally, steel-framed car parks have been designed

vehicles and be of a height and design, which will

using a minimum frequency as a sole measure of

safeguard small children. BS 6180: 1999 'A code of

dynamic performance. SCI publication P076 suggests

practice for barriers in and about buildings' may be

the minimum frequency of the floor (including the

of assistance.

concrete slab, primary and secondary beams, where appropriate) should not be below 3Hz. More recent

Deflection

guidance from the Institution of Structural Engineers

Where clear span construction and high strength steels

suggests an increase, but it appears that this is not

are used for the main beams, deflection may govern the

based on any adverse comment from users or owners.

design. These beams may therefore be pre-cambered to compensate for dead load deflection and to minimise

For vibration, consideration of natural frequency alone

the risk of ponding, when in-situ concrete solutions are

can be misleading, as it is the amplitude of vibration

used. An additional pre-camber may be introduced to

that most people feel. The amplitude can be expressed

compensate for a proportion of the live load deflection

in terms of displacements, but, in practice, this can be

(usually up to 1/3). This has the advantage that the

difficult to measure. As a consequence, most modern

beams have a slight upward bow, which avoids the

Standards describe the sensitivity of human exposure to

optical illusion of a heavily deflected beam when it is, in

vibrations in terms of acceleration amplitudes. In BS

reality, level. The theoretical deflections, allowed for in

6472, accelerations are expressed relative to a ‘base

pre-cambers, do not always occur and care must be

value’, which is adjusted with frequency according to

taken to ensure that any permanent set does not

human perception, so forming a ‘base curve’, as shown

impede the efficient drainage of the slab.

in Figure 15. The ratio of the predicted (or measured) acceleration to the base curve value is then defined as a

Dynamic performance

‘response factor’. A variety of response factor values are

The dynamic performance of floors in buildings has

recommended for different floor types, but there are no

become an important issue in recent times, which has

recommended values for car parks in BS 6472.

led to a review of design practice in this area. In buildings such as hospitals, the dynamic performance can be critical, but in buildings such as car parks, where there is an expectation of disturbance from traffic movement, it is much less important. The human perception of movement in a car park will be less than in

Steel-framed car parks 13

Structural form

1.000 70 car park empty car park full

60 12 x base curve

50 Response factor

0.100

4 x base curve

30 20

Base curve

0.010

40

10 0 0 0.001

1

10 Frequency (Hz)

1

2

3 4 Floor frequency, fo (Hz)

5

6

7

100

Figure 15. Vertical vibration curves taken from BS 6472

Figure 16. Car park dynamic performance

To compensate for this ‘omission’ in the British

To demonstrate the level of accuracy in the analysis

Standard, a study was made of 9 steel-framed car parks

presented here, a car park framed with long span

incorporating long spans. All were constructed in the

cellular beams, which has been subjected to vibration

last 15 years, with no adverse comment about the

tests in Atlanta, Georgia, USA, has been analysed using

dynamic behaviour being known. The examples

the same method. The difference between the measured

included 7 car parks with composite beams and pre-

and calculated values of frequency and response factor

cast units (with a concrete topping or asphalt finish),

was less than 10%.

and 2 with composite beams and a concrete slab using metal decking as permanent shuttering. Secondary

The above results clearly show that there has been a

beam spans ranged from 15.6m to 28m, and floor slabs

recent history of car park construction with low natural

spanned between 3.6 and 7.2m. The most onerous floor

frequencies and high response factors, which have

area in each example was chosen to calculate the

received no adverse comment. The study shows that the

natural frequency and the corresponding response

traditional natural frequency value of 3.0Hz can be

factor. An ‘empty’ case (assuming 1.1% damping) and a

maintained for design, and used with confidence. For

‘full’ case (assuming 2.5kN/m imposed loading and

normal steel-framed solutions, the adoption of this value

4.5% damping) were considered.

leads to bare floors (damping 1.1% with no imposed

2

load) possessing a maximum response factor of The results of the study are shown in Figure 16. Floor

approximately 65. This response factor value can be

natural frequencies ranged from 2.8 to 5.18Hz ‘empty’

used as guidance where more detailed calculations are

and 2.2 to 4.2Hz ‘full’. The natural frequencies tend to

deemed to be appropriate. No guidance is given for a

be lower under full loading because of the higher mass

full car park because the characteristics are different

mobilised. Response factors ranged from 3.6 to 64.5 for

and it is considered that design based on the criterion

the ‘empty’ cases and 0.9 to 26.6 for the ‘full’ cases.

for the empty case is sufficient.

The ratio of the natural frequency ‘full’ to ‘empty’ was nearly always about 0.8, which merely reflects a

This section has been concerned with human-induced

consistent ratio of dead loading only to full loading of

vibration, but excitation may be caused by impact from

0.64 for car park construction. Response factors are

cars running over uneven surfaces or discontinuities,

generally higher for the ‘empty’ case, where the mass

such as expansion joints. Careful detailing and

and damping is less.

workmanship should ensure that any joints are level and can be traversed smoothly, and that the gaps are no larger than necessary. Regular maintenance should prevent the wearing surface from deteriorating.

14 Steel-framed car parks

Structural form

Figure 17. Cross bracing as used at the Genesis car park, World Cargo Centre, Heathrow

Stability

A combination of these methods may be used. For

The stability and robustness of a structure is a vital

example, use a rigid frame across the structure and

structural design consideration. Multi-storey car parks

brace longitudinally at the outside edge of the building.

pose a particular problem because they contain few internal walls. This is especially true of demountable

Whichever method of achieving stability is chosen, it is

structures. There are various methods to ensure

important to consider the construction stage of the

structural stability against horizontal forces; two of the

building as well as the completed structure. The floor

most common options are outlined below.

slab in most cases is designed to carry the horizontal forces to the braced parts of the structure. Until this

a) Braced structure. Suitable bays or cores are placed around the building to provide stability in two

plate has gained sufficient strength it may be necessary to provide temporary plan bracing.

orthogonal directions. Bracing may take the form of cross members or eccentric type bracing. In car parks the eccentric bracing can be used across the structure because it allows relatively unimpeded circulation throughout the floor area. An example of a braced car park structure is shown in case study 1. b) Unbraced structure. In this case the frame is designed as 'rigid'. Moments are transferred from beams into columns via moment connections and stability is gained from the stiffness and continuity of the connections. This may result in the need for haunches in clear span construction. Steel-framed car parks 15

Fire resistance

Fire resistance Steel-framed car parks have been rigorously fire tested in a number of countries (Table 3). These tests demonstrate that most unprotected steel in open sided steel-framed car parks has sufficient inherent resistance to withstand the effects of any fires that are likely to occur. Table 3 lists the maximum temperatures reached in open sided car park tests in four countries. These can be compared with the limiting temperatures of 620°C for beams carrying floor slabs and 550°C for columns, at which failure is expected to occur. Open sided car parks are defined in Approved Document B to the Building Regulations 2000 for England & Wales as having open ventilation of at least 5% of the floor area at each level, at least half of which should be in opposing walls. The fire resistance requirements for open sided car parks in the United Kingdom and Ireland are outlined in Table 4. The dominant period is 15 minutes. Most universal beams and columns will achieve 15 minutes fire resistance without added protection although a small number of sections at the lower end of the range, for example the 152 x 152 x 23UC and 127 x 76 x 13UB, will do so only when less than fully loaded.

Section factor (Hp/A) = Heated perimeter/Cross Sectional Area. These are calculated for most common situations in the Corus sections brochure.

The data on limiting section factors can also be expressed as a function of load ratio as defined in

In general, where a section does not have 15 minutes inherent fire resistance, it is usually more efficient to increase the section size than to fire protect.

BS 5950 Part 8, Code of Practice for Fire Resistant Design. A fully loaded beam or column is normally assumed to have a load ratio of 0.6 for the fire limit state. Provided the load ratio is less than 0.6, most universal beams & columns will achieve 15 minutes fire resistance

Table 3. Fire tests in various countries Full scale fire tests

* Increased to 60 minutes for compartment walls separating buildings + Increased to 30 minutes for elements protecting a means of escape ◊ The European Supplement to Approved Document B outlines details of beams and columns, in terms of section factors, which are deemed to satisfy the requirement to achieve 15 minutes fire resistance without protection. I. Beams supporting concrete floors, maximum section factor = 230m-1 or open section beams with a minimum lower flange thickness ≥ 9mm. II. Free standing columns, maximum section factor = 180m-1 or open section columns with a minimum lower flange thickness ≥ 12.5mm. III.Wind bracing and struts, maximum section factor = 210m-1 or flats, angles and channels with a thickness ≥ 10mm or hollow sections with a wall thickness ≥ 6mm. # A note similar to that in the European Supplement to Approved Document B exists in Technical Standards Part D, page 33D. This says that, where the topmost storey of the building is at a height not more than 18m above ground, the requirement for the structural frame will be met by: I. Beams supporting concrete floors, each beam having a maximum section factor = 230m-1. II. Free standing columns, each having a maximum section factor = 180m-1 III.Wind bracing and struts, each having a maximum section factor = 210m-1

without fire protection. The exceptions, and the

Maximum measured steel temperature

maximum load ratios to achieve 15 minutes fire

Beam

Column

resistance for non-composite construction, are provided

UK

275°C

360°C

in tables 5 and 6 on the right:

Japan

245°C

242°C

USA

226°C

–

Australia

340°C

320°C

Table 4. Open sided car parks Requirements from regulations

Height of top floor Up to 30m

Over 30m

England and Wales

15 minutes * + ◊

60 minutes

Scotland

30 minutes #

30 minutes

Northern Ireland

15 minutes * +

Not permitted

Republic of Ireland

15 minutes *

Not permitted

16 Steel-framed car parks

Fire resistance

Table 5. Maximum load ratios for 15 minutes fire resistance – UB exceptions* UB section size

Section factor (Hp/A)

Maximum load ratio to achieve 15 minutes fire resistance

127x76x13UB

285m-1

0.54

152x89x16UB

275m

0.54

178x102x19UB

270m

0.54

203x133x25UB

250m

0.57

254x102x22UB

285m

0.49

254x102x25UB

259m

0.56

305x102x25UB

285m

0.48

305x102x28UB

255m

0.58

356x127x33UB

250m

0.58

406x140x39UB

245m

0.59

-1

-1

-1

-1

-1

-1

-1

-1

-1

* Where design is governed by serviceability, the majority of these sections will achieve 15 minutes fire resistance. This should be assessed on a case by case basis.

Table 6. Maximum load ratios for 15 minutes fire resistance – UC exceptions UC section size

Section factor (Hp/A)

Slenderness ratio*

Maximum load ratio to achieve 15 minutes fire resistance

152x152x23UC

310m-1

81

N/A, Choose next in the section range

152x152x30UC

240m

78

0.36

152x152x37UC

190m

77

0.45

203x203x46UC

205m

58

0.51

203x203x52UC

185m

58

0.58

-1

-1

-1

-1

*Assumes an effective length of 3 metres. The actual failure temperature is a function of the slenderness ratio.

In practice, many sections will have load ratios lower than 0.6. The latest version of BS 5950 Part 8 was published in 2003, after the European Supplement and the most recent version of Technical Standard D. This differentiates between composite and non-composite beams and between different degrees of shear connection. The effect of this will be that composite beams will be assumed to have lower failure temperatures than non-composite beams. This could be taken to mean that some additional beams will not achieve 15 minutes inherent fire resistance when designed compositely. However, composite beams have enhanced robustness because of the effects of continuity in the floors. This has been investigated and the results published in Report No. 75 – Fire Safety in Open Car Parks, published by the European Convention for Constructional Steelwork, which concludes that, in the event of a fire in an open car park, no failure will occur.

Steel-framed car parks 17

Durability

Durability A car park should be designed to give the best possible

top surface of the concrete slab should be protected

return on investment and should therefore be

with an appropriate proprietary waterproofing system.

maintenance free as far as possible. Maintenance

Manufacturers guidance should be followed for the

requirements, and how they should be carried out, are

correct choice of product and application.

described in the ICE publication “The inspection and maintenance of multi-storey car parks”. Maintenance is

Metal decking

of particular importance to ensure that drainage gullies

G275 galvanizing (275g/m2 of zinc) is the standard

and downpipes are clear of debris to enable water to

protective coating for composite steel decking. This

drain efficiently from the car park.

level of corrosion protection to the upper surface of the decking will be sufficient, provided adequate provision

Car parks, by their very nature exist in environments that

has been made to prevent the ingress of water (using

are far from ideal. The air is often contaminated with

reinforcement to control cracking, and waterproofing the

fumes from car engines. The surfaces of the structure

top surface of the concrete). The underside of the

may be sprayed with water, which in winter can be

decking should be given additional protection in the

contaminated by de-icing salts and other highly

form of a pre-applied coating or epoxy paint applied in-

corrosive elements that can percolate through cracks in

situ. Such an additional layer of protection has the

the concrete slab. Although the effect of these can be

advantage that it can be regularly inspected and

minimised by good drainage design, crack control,

remedial work undertaken if required. However, it is

and /or the application of protection to the top surface of

recommended that Corus be consulted on durability and

the slab, it is still necessary to give complete protection

future maintenance issues at an early stage if this

to those components within the car park, which are

solution is to be adopted.

likely to be in close contact with these contaminants. The major elements are the steel frame and the

Waterproofing

concrete, or composite floor slabs.

Car parks require treatment against the effects of an external climate. The car park environment can be very

The steel frame

onerous, especially where aggressive snow and ice

Steel is a durable framing material. It will, if protected

clearing methods are adopted. It is therefore

correctly, give a long life with minimal maintenance.

recommended that at least the top deck of the car park is waterproofed with a traditional bituminous membrane

In most cases all that is required is a repaint at the first

or liquid applied seamless coating. It is also good

maintenance period, which can be 20 to 30 years or

practice to treat other floors to prevent ingress of water.

more, depending on the initial protection specified.

It is important to specify the correct product and ensure

Three suggested treatments are given in Table 7. The

that installation and maintenance are fully in accordance

durability of the protection system is primarily influenced

with the supplier’s recommendations.

by the corrosivity of the environment. The corrosivity categories are based upon those given in ISO 12944

With all floors it’s necessary to provide adequate falls and

Part 2 and ISO 9223.

drainage to prevent the build up of water on the slabs.

Concrete floors

There is a growing trend to use a lightweight roof over

The concrete within a car park is particularly susceptible

the top parking deck. This gives added protection to the

to deterioration, so grade 50 concrete should usually be

top floor of the car park allowing users to park in all

specified. Pre-cast units are generally more durable than

weathers. The aesthetic appeal of a car park can be

in-situ concrete due to factory controlled production

significantly enhanced by this method enabling the park

conditions. It is recommended therefore, that one of the

to blend in with the urban environment. The long-term

pre-cast systems outlined above should be used with a

benefits of reduced maintenance can far outweigh the

limited amount of structural topping. To minimise the

initial cost of this approach. The car parks at Aylesbury

percolation of corrosive fluids through cracks floors

and Guildford typify this method of construction.

should be sloped at 1:60 falls to aid drainage, and the

18 Steel-framed car parks

Durability

Table 7. Suggested corrosion protection systems Car parks Environmental category (Note 8)

C3

C4

C5

System number

B12

E6

E9

C3

20+

25

30

C4

15-20

15-20

25

C5

8-20

12

20

N/A

Blast clean to Sa 21⁄2

Blast clean to Sa 21⁄2

Anticipated durability of the coating system in years and environment categories (Notes 1 & 2)

Shop applied

Surface preparation (BS 7079: Part A1) Coatings (Note 5)

Site applied

Coatings

Relative costs (Note 6)

Hot dip galvanize to BS EN ISO 1461 (Note 3)

Zinc rich epoxy primer

40µm

Zinc rich epoxy primer

40µm

High build epoxy MIO

100µm

One or two coats High build epoxy MIO

200µm

85µm

None (Note 4)

High build epoxy MIO (Note 7)

1

1.18

100µm

High solid aliphatic polyurethane finish

80µm

1.55

(Based on information extracted from ‘A Corrosion Protection Guide: For steelwork exposed to atmospheric environments’, see Bibliography) Notes 1. Coating system durability given in the table is based on practical experience. It is the expected life, in years, before first major maintenance. This is taken as degradation level Ri3 from ISO 4628 Part 3 (1% of surface area rusted). It should be noted that this does not imply a guarantee of life expectancy. In coastal areas, the coating life expectancy may be reduced by up to 30%. 2. The durability of galvanized steelwork is derived from the figures in BS EN ISO 14713. 3. Galvanizing should be carried out to Standard BS EN ISO 1461. 4. Where painting of galvanized steelwork is required for aesthetic or other reasons, suitable systems from ISO 12944 may be used. 5. The thickness values given for primers are the total thickness used and may include a prefabrication primer. 6. The relative costs given here are for guidance. There will be considerable variation that may typically be +/- 50% for a variety of reasons. Quotations should be obtained before making the final selection of the protective treatment. 7. It should be noted that the colour of micaceous iron oxide (MIO) is limited. 8. Environmental categories are based on those given in ISO 12944 and ISO 9223.

Figure 18. Guildford 946 space Car Park adjacent to railway and local housing

Figure 19. Aylesbury 600 spaces on 5 levels developed by Safeway Stores plc for Aylesbury Vale District Council

Steel-framed car parks 19

Refurbishment One of steel's major advantages is the ease with which it can be refurbished and adapted. Car parks in steel are no different in this respect. Where examples can be found they have been refurbished with minimal expense and great success as at the refurbished Waitrose car park at Weybridge.

Before refurbishment

After refurbishment

Refurbished interior Figure 20. Waitrose car park at Weybridge.

20 Steel-framed car parks

Aesthetic design Steel car park structures have been designed to accept all types of external cladding. Examples include Plastisol sheets as at Poole, steel mesh panels as at Aldershot, steel mesh and fins at Milton Keynes and brick as at Aylesbury, Guildford and Tallaght. There are various steel cladding systems ranging from the simple sheet to sophisticated composite panels. All are compatible with the steel frame. Brick cladding of steel frames is well proven for offices, car parks and many other structures. Steel’s inherent

Figure 23. Avebury Boulevard multi-storey car park, Milton Keynes.

accuracy is a positive advantage when attaching brickwork support systems. The cladding may be designed to be load bearing as well as aesthetic. In particular crash barriers have been designed as an integral part of the cladding system. These may be load resistant (stiff) or energy absorbing (flexible). The steel frame provides an excellent interface for connection of either type.

Figure 21. Poole car park.

Figure 24. Tallaght multi-storey car park.

Figure 22. Royal Pavillion car park, Aldershot.

Steel-framed car parks 21

Commercial viability The cost per space for a basic average-sized (250 spaces) multi-storey car park is in the region of £3,000-£4,000 (2002 figures) inclusive of framework, floors, barriers, foundations and cladding. The cost of a steel frame in real terms has decreased appreciably over the last few years through greater efficiency in both the steel manufacturing and fabrication industries. The shorter construction period made possible through the use of a steel frame and consequently the earlier return on investment increases the commercial viability. The elimination of fire protection costs has had a major influence in making a steel-framed car park one of the most competitive options available.

Midsommer Boulevard car park Milton Keynes

Latest developments

Latest developments Demountable car parks The exponential upward trend in the use of cars in the UK is resulting in the need to provide a greater number of car parks. Large companies and institutions especially, have a growing need for parking facilities. This need may be met in many cases by the use of demountable structures, to give an eminently flexible solution to the parking problem. Steel is considered to be the only practical solution that can be constructed as demountable. The car park at Luton is an example of a car park, which could be demountable with some minor modifications.

Figure 25. Simple car park in Luton

Wholly automatic multi-storey car parks This form of car park takes half the volume of a conventional car park to store the same number of cars. This is because these steel-framed car parks do not require access ramps or roadways within the car storage area. The driver parks the cars on a robot trolley within an entrance module. From this point the trolley takes the car to an empty parking space. When the driver wants the car back, it is retrieved by a robot trolley and returned to an exit module. Construction is simply a steel framework with cladding to match the local environment. Since this form of car

Figure 26. Fully automated car park building in Istanbul

park requires less energy to run, operating costs are lower than for a conventional car park. This form of car park can be built either above or below ground.

Steel-framed car parks 23

Sizing data sheets

Sizing data sheets Car space

Assumptions

6m Aisle

Car space

appropriate for one bay of a car park

7.2m

3.6m

Beam - B

Beam A

3.6m

• Design is given for internal and edge beams where

Edge Beam

following assumptions

Beam A

• Imposed loading is taken as 2.5kN/m2 • No account is taken of pattern loading

15.9m

• Grade S355 to BSEN10025:1993 is used for all main

3 Stalls (car spaces)

Beam A

The car park layouts shown are based upon the

Car space

and secondary beam steel • Grade S275 to BSEN10025:1993 is used for all ties • Approximate weights of steel given are based on a car park 72m long x 32m wide with car parking spaces at 2.4m wide. An allowance of 4% for connections and bracing has been assumed • All in-situ concrete is normal weight, grade 50 • Beams and slabs are unpropped (vertically) • Column sizes are based on the lower length of a 4-storey car park • Beams have been chosen to give a minimum frequency of 3.0Hz • Imposed load deflection limit: Span/360 • Total load deflection limit: Span/150 • Pre-camber approximately equivalent to deflection due to dead load + 1/3 deflection due to imposed load The structural sizes presented for layouts 1 to 4 have been derived on the assumption of balanced loading and effective temporary restraint of the compression flanges during construction. For further guidance on this issue refer to SCI publication SCI-P287.

Layout 1 Floor construction: 75mm deep precast planks. Composite slab depth – 140mm overall Beam ‘A’: 610 x 229 x 101 UB, grade S355 Composite with 104 – 19mm diameter shear studs x 95mm long Camber approximately 80mm Beam ‘B’: 610 x 229 x 101 UB, grade S355 Composite with 30 – 19mm diameter shear studs x 95mm long Columns: 305 x 305 x 97 UC, grade S355 Approximate weight of steel: 45.2 kg/m2 (0.86 tonne/parking space) Overall depth of construction: 743mm

24 Steel-framed car parks

Sizing data sheets

2 Stalls (car spaces)

Beam D

4.8m

Tie

Beam D Edge Beam

3 Stalls (car spaces)

Beam C

7.2m

Tie

Edge Beam

Beam C

15.9m 15.9m

Layout 2

Layout 3

Floor construction:

Floor construction:

150mm deep hollow core precast units.

100mm deep precast planks.

Composite slab depth – 200mm overall

Composite slab depth – 150mm overall

Beam ‘C’:

Beam ‘D’:

762 x 267 x 147 UB, grade S355

610 x 229 x 125 UB, grade S355

Composite with 148 – 19mm diameter shear studs x

Composite with 104 – 19mm diameter shear studs x

120mm long

120mm long

Camber approximately 95mm

Camber approximately 85mm

Tie:

Tie:

203 x 133 x 25 UB, grade S275

152 x 152 x 23 UC, grade S275

Columns:

Columns:

305 x 305 x 118 UC, grade S355

254 x 254 x 73 UC, grade S355

Approximate weight of steel:

Approximate weight of steel:

45.2 kg/m2 (0.86 tonne/parking space)

36.2 kg/m2 (0.69 tonne/parking space)

Overall depth of construction:

Overall depth of construction:

743mm

762mm

Steel-framed car parks 25

Sizing data sheets

7.2m

Beam F

Tie

Tie

Beam F

Beam F

15.9m

3 Stalls (car spaces)

Beam E

3 Stalls (car spaces)

7.2m

Beam F

Tie

Edge Beam

Beam E

15.9m

Layout 4

Layout 5

Floor construction:

Floor construction:

210mm deep hollow core precast units.

110mm pre-cast “Montex” slabs.

Composite over 1m width

Expanding grout infill with strip waterproof membrane

Beam ‘E’:

Beam ‘F’:

610 x 210 / 305 x 152 Asymmetric Cellular Beam,

457 x 191 x 74 UB, grade S355

grade S355

Composite with 74 – 19mm diameter shear studs x

400mm diameter cells @ 600mm centres

95mm long

Top tee

– 533 x 210 x 122 UB

Camber approximately 105mm

Bottom tee

– 305 x 305 x 158 UC

Composite with 99 – 19mm diameter shear studs x

Tie:

120mm long

127 x 152 x 19 tee, grade S275

Tie:

Columns:

203 x 133 x 25 UB, grade S275

203 x 203 x 46 UC, grade S355

Columns:

Approximate weight of steel:

305 x 305 x 118 UC, grade S355

40.8 kg/m2 (0.78 tonne/parking space)

Approximate weight of steel:

Overall depth of construction:

30.2 kg/m (0.58 tonne/parking space)

567mm

2

Overall depth of construction: 819mm

26 Steel-framed car parks

Sizing data sheets

Beam H

Beam H

15.9m

7.2m 3 Stalls (car spaces)

J Beam 3.6m 3.6m

J Beam

7.2m 3 Stalls (car spaces)

Beam G

Tie 3.6m

Beam G

Beam H

Tie 3.6m

Edge Beam

Beam G

15.9m

Layout 6

Layout 7

Floor construction:

Floor construction:

Comflor 70, 1.2mm gauge

Comflor 70, 1.2mm gauge

Slab 120mm thick

Slab 120mm thick

Beam ‘G’:

Beam ‘H’:

533 x 210 x 82 UB, grade S355

533 x 210 x 82 UB, grade S355

Composite with 86 – 19mm diameter shear studs x

Composite with 86 – 19mm diameter shear studs x

95mm long

95mm long

Camber approximately 100mm

Camber approximately 100mm

Tie:

Beam ‘J’:

127 x 152 x 19 tee, grade S275

533 x 210 x 82 UB, grade S355 Composite with 30 – 19mm diameter shear studs x

Columns:

95mm long

203 x 203 x 52 UC, grade S355 Columns: Approximate weight of steel:

254 x 254 x 89 UC, grade S355

31.4 kg/m2 (0.60 tonne/parking space) Approximate weight of steel: Overall depth of construction:

37.0 kg/m2 (0.71 tonne/parking space)

648mm Overall depth of construction: 648mm

Steel-framed car parks 27

Case studies

Case study 1 World Cargo Centre, Heathrow.

Brief

Technical information

The brief was to design a 1000-space multi-storey car

Area (suspended): 19,100m2

park for staff at Heathrow’s World Cargo Centre to suit

No of floors: 5 including the ground floor

the site constraints. The car park was to incorporate a

No of parking spaces (incl. ground floor): 1,000

small retail area at ground floor and meet the requirements of a gold standard award. It was to be durable, fit for purpose and give value for money.

Steel tonnage: 728T Construction period: 39 weeks Date completed: March 1997

Attributes • 5 levels of open single deck parking.

Design: Steel frames at 7.2m centres, 150 deep hollow core units with 75mm structural topping.

• Minimum clear headroom of 2400mm.

Façade: Aluminium Cladding

• Galvanized protection system.

Total construction costs: £3,900,000

• Waterproof membrane to top floor and first floor

Total cost per space: £3,900

retail area. • Steel vehicle impact barrier system

Total cost per m2 (including ground floor): £163 Type of contract: Design & Build Client: BAA plc

Special features The construction process was radically re-engineered to

Architect: HGP Architects

reduce cost and time and to develop what was to become

Engineer/fabricator: Bison Structures Ltd

known as the “World Class Construction Process”.

Management contractor: MACE

Efficiency and economy in the use of structural steelwork by standardisation, modularization and a simple design approach resulted from the innovative design and construction processes.

28 Steel-framed car parks

Case studies

Case study 2 Buttercrane Centre multi-storey car park, Co Down.

Brief

Technical information

The client’s brief for this project included an extension to

Area (suspended): 12,300m2

the retail area of an existing shopping center plus the

No of floors: 5 including the ground floor

provision of approximately 600 car parking spaces. The

No of parking spaces (incl. ground floor): 606

car parking areas were to be bright and welcoming to the shoppers whilst keeping within tight budget costs.

Steel tonnage: 500T Construction period: 30 weeks total

Attributes

Date completed: November 1997

• Nine levels of parking on split deck construction

Design: Pre-cast concrete slab (75mm thick) with in-situ topping on clear span steel frame using composite cellular beams and universal columns.

• Clear span construction using compositely designed, cambered cellular floor beams. High specification paintwork and good quality lighting provide a bright

Façade: Facing brickwork Total construction costs: £2,445,000

and comfortable environment • Top decks are overcoated with an elastomeric

Total cost per space: £4,035

waterproof membrane which is colour coded to

Total cost per m2 (including ground floor): £171

indicate the parking areas

Type of contract: JCT 80 – negotiated contract

• The structure and foundations were designed and

Client: Buttercrane Centre Ltd

constructed to allow for an additional two levels of car

Architect: WDR & RT Taggart

parking in the future

Engineer: WDR & RT Taggart Contractor: O’Hare & McGovern

Special features A 225mm pre-camber in the cellular beams was used for

Fabricator: Ballykine (Structural Engineers) Ltd

natural water shedding. This was provided at no

Cellular beams supply: Westok Structural Services Ltd

additional cost.

Managing agents: Lambert Smith Hampton

Steel-framed car parks 29

Case studies

Case study 3 Stockley Business Park, Heathrow.

Brief

Technical information

Stockley Park is an intensively developed business park

Area (suspended): 3,100m2

containing a mixture of buildings and surface parking

No of floors: 1 additional floor (suspended)

located near Heathrow Airport. 170 additional car

No of parking spaces (incl. ground floor): 178

parking spaces were required. The design and construction programme was very short and the

Construction period: 16 weeks

surrounding environment dictated a structure of high

Date completed: December 1995

aesthetic and constructional quality.

Design: Steel portal frames of tapered I section plate girders with tubular legs and tie rods. The deck comprises pre-cast concrete and glass panels.

Attributes

Façade: Open

• High architectural quality

Total construction costs: £1,200,000

• Pre-fabrication allowed very rapid design and

Total cost per space: £6,742

construction (26 weeks from concept to completion) • Piled foundations were used because of the difficult ground conditions • Open design improves the safety of the environment,

Total cost per m2 (including ground floor): £190 Type of contract: Traditional Client: BP Properties Ltd

enhanced by metal halide lighting and improved all-

Architect: Broadway Malyan

round observation

Engineer: Ove Arup & Partners

• Narrow columns save floor space and allow very tight stall widths to be used • Slim pre-cast and glass floor reduced the height and access ramp length Special features • Clear span construction allowed the car park to be built without losing ground floor parking. • Very tight spacing of bays at 2.2m • Marine Styling.

30 Steel-framed car parks

Main contractor: Try Construction Ltd Fabricator: Dyer (Structural Steelwork) Ltd

Case studies

Case study 4 Bradford city centre multi-storey car park.

Brief

The use of VCM resulted in minimum cut and fill

The Client’s brief for this project was to produce a

operations and idealized internal circulation without

modern, safe car park on a restricted site, to service the

conflicting zones.

needs of shoppers visiting Bradford city centre. The car park was to provide around 430 spaces next to the

The deck construction comprises self-finished Trideck

existing Co-op store, Sunwin House. After being in the

units, the designs of which are also the property of Hill

planning stages for a number of years Clugston

Cannon (UK) LLP, subject to a UK patent, and are

managed to bring in some innovative value engineering

available for use under licence.

ideas to take the project through to reality. Attributes • 7 levels of parking utilising a Vehicle Circulation Model (VCM) construction technique. • A combination of the steel frame and pre-cast decks

Technical information Area (suspended): 9456m2 No of floors: 7 including the ground floor No of parking spaces (incl. ground floor): 432

has enabled a lightweight easily constructed car park

Steel tonnage: 410T

on a very restricted city centre site.

Construction period: 48 weeks

• The use of clear span construction and open sides to

Date completed: October 2003

the car park give a light and open environment in which to park. A high level of low energy lighting contributes to the enhancement of the environment.

Design: Pre-cast units laid on the steel frame Façade: Insulated cladding, mesh panels, low level facing blockwork

• Cost effective design solution.

Total construction costs: £3,590,000

• Clear span construction using compositely designed,

Total cost per space: £8,310

cambered cellular floor beams. • The clear span construction has helped to provide a safe environment in which to park.

Total cost per m2 (including ground floor): £325 Type of contract: Design and Build Client: United Co-Operatives

• Top decks are overcoated with an elastomeric waterproof membrane which is colour coded for userfriendly parking.

Architect: Bowman Riley Engineer: BSCP Parking consultant: Hill Cannon (UK) LLP

Special features

D&B main contractor: Clugston Construction

As an alternative to a split level layout the VCM

Fabricator: Caunton Engineering

circulation system was adopted. This system is the property of Hill Cannon (UK) LLP, Royal Chambers, Station Parade, Harrogate, is subject to a UK patent no GB2 269 610 B and is available for use under licence.

Steel-framed car parks 31

Case studies

Case study 5 The Parishes multi-storey car park, Scunthorpe.

Brief

property of Hill Cannon (UK) LLP, Royal Chambers,

Parking facilities are a strategic element of ‘The

Station Parade, Harrogate, is subject to a UK patent no

Parishes’, a £40 million redevelopment of Scunthorpe

GB2 269 610 B and is available for use under licence. The

Town Centre. The ground plus four level 700 space car

use of VCM resulted in minimum cut and fill operations

park provides safe, secure parking for shoppers, patrons

and idealized internal circulation without conflicting zones.

of the 7 screen cinema complex and other town centre amenities and facilities.

Designed to comply with the requirements of the AA/Association of Chief Police Officers ‘Secure Car Park

Attributes

Award’ scheme.

• 4 levels of parking utilising a Vehicle Circulation Model (VCM) construction technique • A combination of the steel frame and pre-cast hollow core plus structural topping decks has resulted in a lightweight easily constructed car park on the site of an existing surface car park • The use of clear span construction and open sides

An enclosed link bridge at second floor level provides sheltered access to a terrace area, the main retail elements and the cinema complex Technical information Area (suspended): 11,900m2

create a light and open environment. A high level of

No of floors: 5 including the ground floor

low energy lighting and CCTV surveillance contributes

No of parking spaces (incl. ground floor): 700

to the enhancement of the environment

Steel tonnage: 510T

• Circa 30 disabled spaces, motorcycle and cycle parking • Office, Shopmobility and storage facilities are

Construction period: 48 weeks Date completed: October 2002

incorporated at ground level • Curtain wall glazing creates light, airy feel to stairs

Design: Pre-Con pre-cast units on the steel frame

• Cost effective design solution

Façade: Steel cladding, curtain walling and low level facing blockwork

• Clear span construction using compositely designed,

Total construction costs: £3,000,000

cambered cellular floor beams • The clear span construction has helped to provide a safe environment in which to park • Top decks are overcoated with an elastomeric

Total cost per space: £4,286 Total cost per m2 (including ground floor): £202 Type of contract: Design and Build Client: Quintain

waterproof membrane which is colour coded for userfriendly parking

Architect: CDA Architects, Brighton Engineer: Ward Cole, Lincoln

Special features

Parking consultant: Hill Cannon (UK) LLP

As an alternative to a split level layout the VCM

Contractor: Clugston Construction

circulation system was adopted. This system is the

Fabricator: Conder Structures

32 Steel-framed car parks

Case studies

Case study 6 Ipswich station multi-storey car park.

Brief The brief was to design and build a 435 space

• A wide range of elevational finishes to compliment any surrounding local environment.

multi-storey car park to service rail commuters. The car park was designed to blend in with the adjacent

Construction was undertaken adjacent to a live railway

Victorian architecture of the listed station building and

line. Furthermore, the station remained operational

surrounding private residences. The car park was also

throughout construction, and Bourne Parking carefully

designed for, and subsequently successfully achieved,

managed the interface with general public, commuters

the Secured Car Park Award. The project was won in a

and station traffic.

competitive tender scenario. Attributes

Technical information

• 7 split levels of parking.

Area (suspended): 7,000m2

• All steel components fully galvanised to 85 microns DFT.

No of floors: 7 including the ground floor

• High performance polymer modified asphalt

No of parking spaces (incl. ground floor): 435

waterproof system to top floor. • Untensioned corrugated profile safety barrier. • High quality architectural appearance including in-situ

Steel tonnage: 400T Construction period: 36 weeks Date completed: October 2001

brickwork and metal cladding. Design: 16m clear span Montex structural steelwork frame and 110mm deep Montex precast concrete floor units.

Special features The multi-storey car park was based upon Bourne

Façade: Brickwork and architectural metalwork Total construction costs: £2,600,000

Parking’s unique prefabricated Montex modular technology, which provides the following key benefits for multi storey car parks:

Total cost per space: £5,977 Total cost per m2 (including ground floor): £265 Type of contract: Design and Build

• High quality factory produced building solutions.

Client: Anglia Railways/Railtrack

• User friendly and safe clear span column free layouts

Architect: Charter

that meet the recommendations of the Secured Car Park Award.

Engineer: Whitby Bird & Partners Contractor: Bourne Parking Ltd

• Fast track construction techniques to ensure the shortest possible programme.

Fabricator: Bourne Parking Ltd

• Phased construction and planned logistical management for minimal disruption to existing facilities. • Reduced whole life cost of the building as a result of low, long-term maintenance requirements.

Steel-framed car parks 33

Bibliography

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BS 6399: Part 1: 1999 Code of practice for dead and

Parks" British Steel General Steels, Redcar. UK July

imposed loads.

1989. BS 6472: 1992 Guide to evaluation of human exposure Murray, T.M., Floor vibration testing and analysis of

to vibration in buildings.

SMART BEAM floors - parking garages, Atlanta, Georgia. Report by Structural Engineers, INC for CMC

A Corrosion Protection Guide for Steelwork in

Steel Group.

atmospheric environments. Corus Construction & Industrial 2004.

I D Bennetts, D J Proe, R R Lewins, I R Thomas "Opendeck Car Park Fire Tests". BHP Melbourne Research

Design guide on the vibration of floors (P076), The Steel

Laboratories. August 1985.

Construction Institute, 1989

I D Bennetts, D J Proe, R R Lewins, I R Thomas "Fire and Unprotected Steel in Closed Car Parks". BHP Melbourne Research Laboratories 1988. "The Scranton Fire Test" American Iron and Steel Institute Brochure. Dr B R Kirby "Reassessment of the fire resistance requirements of tall, multi-storey open sided steelframed car parking structures". British Steel Swinden Technology Centre. ECCS technical note 75 "Fire Safety in Open Car Parks" Modern Fire Engineering 1993 IISI "Fire Engineering Design for Steel Structures": State of the art 1993. Eurofer "Steel and Fire Safety: A Global Approach" 1990. "Design Recommendations for Multi-Storey and Underground Car Parks" (Third edition): Institute of Structural Engineers 2002. “The inspection and maintenance of multi-storey car parks” ICE, 2002. "Architecture and steel in construction" Blanc, McEvoy, Plank: E & FN Spon & The Steel Construction Institute 1992. BS 5950 Structural use of steelwork in building. BS 6180: 1995. A code of practice for barriers in and about buildings.

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Support from CC&I

Support for the construction industry from Corus Construction & Industrial Guidance on the design and use of structural sections and plates. Corus provides free advice to the construction industry covering all aspects of the design, specification and use of its range of construction products. Corus Construction and Industrial manufactures structural sections and plates for building and civil engineering applications. Advice is provided by our team of qualified engineers with extensive experience in the design and construction of buildings and bridges. Specialist advice on fire engineering, durability and sustainability is also available. Our regional network of engineers covers the whole of the UK and Ireland and is supported by a dedicated design team based at our manufacturing centre in Scunthorpe. General enquiries on other construction products and systems manufactured by Corus will be routed to our Construction Centre who will connect you to the appropriate source of market and product expertise. You can contact us as follows: Technical Hotline +44 (0) 1724 405060 Facsimile +44 (0) 1724 404224 Literature Line +44 (0) 1724 404400 Email [email protected] Web www.corusconstruction.com Corus Construction & Industrial Technical Sales & Marketing PO Box 1 Brigg Road Scunthorpe North Lincolnshire DN16 1BP

Steel-framed car parks 35

www.corusgroup.com Care has been taken to ensure that this information is accurate, but Corus Group plc, including its subsidiaries, does not accept responsibility or liability for errors or information which is found to be misleading. Copyright 2004 Corus Designed and produced by Orchard Corporate Ltd.

Corus Construction & Industrial Technical Sales & Marketing PO Box 1 Brigg Road Scunthorpe North Lincolnshire DN16 1BP T +44 (0) 1724 405060 F +44 (0) 1724 404224 E [email protected] www.corusconstruction.com English language version

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